1. Field of the Invention
The present invention relates to separators and more particularly to a device for separating blood plasma from cellular material of the type disclosed in commonly assigned application Ser. No. 247,483, filed Apr. 25, 1972, now U.S. Pat. No. 3,849,072.
2. Description of the Prior Art
With the development of modern pathological laboratories, it has become the common practice to send blood samples to a centralized laboratory facility for analysis. The normal procedure requires that the patient's blood sample be taken at a doctor's office or a clinic and thereafter mailed in a proper container to a centrally located laboratory to be tested. In many instances, it is desirable that the cellular material contained in a blood sample be separated from the blood plasma shortly after the sample is taken from the patient and prior to mailing. Centrifuging has become the accepted method for separation of the suspended cellular material from the blood plasma.
It is known to separate blood into its component parts by centrifugation, for example, the assembly disclosed in U.S. Pat. No. 2,460,641. However, this particular assembly does not employ a means for sealing the separated plasma or serum phase from the cellular phase.
It is also known to provide assemblies for manually separating the plasma or serum phase from the cellular phase, for example, as disclosed in U.S. Pat. Nos. 3,586,064; 3,661,265; 3,355,098; 3,481,477; 3,512,940 and 3,693,804. In all of these devices the serum is collected in a blood collection container and means are provided for separating the plasma or serum phase from the cellular phase employing filters, valves, transfer tubes or the like.
It is also known to provide assemblies for the sealed separation of blood in which a piston is actuated by centrifugal force such as is disclosed in U.S. Pat. Nos. 3,508,653 and 3,779,383. These devices use either a distortable piston made of a resilient material or valve means associated with the piston to affect a sealed separation after centrifugation.